﻿/* 
* Auto Expanding Text Area (1.2.2)
* by Chrys Bader (www.chrysbader.com)
* chrysb@gmail.com
*
* Version 1.2.3 update
* by Richard Vallee
* richardvallee@gmail.com
*
* Special thanks to:
* Jake Chapa - jake@hybridstudio.com
* John Resig - jeresig@gmail.com
*
* Copyright (c) 2008 Chrys Bader (www.chrysbader.com)
* Licensed under the GPL (GPL-LICENSE.txt) license. 
*
*
* NOTE: This script requires jQuery to work.  Download jQuery at www.jquery.com
*
*/

(function(jQuery) {

    var self = null;

    jQuery.fn.autogrow = function(o) {
        return this.each(function() {
            new jQuery.autogrow(this, o);
        });
    };


    /**
    * The autogrow object.
    *
    * @constructor
    * @name jQuery.autogrow
    * @param Object e The textarea to create the autogrow for.
    * @param Hash o A set of key/value pairs to set as configuration properties.
    * @cat Plugins/autogrow
    */

    jQuery.autogrow = function(e, o) {
        this.options = o || {};
        this.dummy = null;
        this.interval = null;
        this.line_height = this.options.lineHeight || parseInt(jQuery(e).css('line-height'));
        this.min_height = this.options.minHeight || parseInt(jQuery(e).css('min-height'));
        this.max_height = this.options.maxHeight || parseInt(jQuery(e).css('max-height')); ;
        this.textarea = jQuery(e);
        this.expand_tolerance = (!isNaN(this.options.expandTolerance) && this.options.expandTolerance > 0) ? this.options.expandTolerance : 4;

        if (isNaN(this.line_height))
            this.line_height = 0;

        // Only one textarea activated at a time, the one being used
        this.init();
    };

    jQuery.autogrow.fn = jQuery.autogrow.prototype = {
        autogrow: '1.2.3'
    };

    jQuery.autogrow.fn.extend = jQuery.autogrow.extend = jQuery.extend;

    jQuery.autogrow.fn.extend({
        init: function() {
            var self = this;
            this.textarea.css({ overflow: 'hidden', display: 'block' });
            this.textarea.bind('focus', function() { self.startExpand() }).bind('blur', function() { self.stopExpand() });
            this.checkExpand();
        },

        startExpand: function() {
            var self = this;
            this.interval = window.setInterval(function() { self.checkExpand() }, 400);
        },

        stopExpand: function() {
            clearInterval(this.interval);
        },

        checkExpand: function() {
            if (this.dummy == null) {
                this.dummy = jQuery('<div></div>');
                this.dummy.css({
                    'font-size': this.textarea.css('font-size'),
                    'font-family': this.textarea.css('font-family'),
                    'width': this.textarea.css('width'),
                    'padding': this.textarea.css('padding'),
                    'line-height': this.line_height + 'px',
                    'overflow-x': 'hidden',
                    'position': 'absolute',
                    'top': 0,
                    'left': -9999
                }).appendTo('body');
            } else {
                // If the dummy was already created, show it as it is hidden after expansion
                this.dummy.show();
            }

            // Strip HTML tags
            var html = this.textarea.val().replace(/(<|>)/g, '');

            // IE is different, as per usual
            if (jQuery.browser.msie) {
                html = html.replace(/\n/g, '<BR/>new');
            }
            else {
                html = html.replace(/\n/g, '<br/>new');
            }

            if (this.dummy.html() != html) {
                this.dummy.html(html);
                if (this.max_height > 0 && (this.dummy.height() + (this.expand_tolerance * this.line_height) > this.max_height)) {
                    this.textarea.css('overflow-y', 'auto');
                    if (this.textarea.height() < this.max_height) {
                        this.textarea.animate({ height: (this.max_height + (this.expand_tolerance * this.line_height)) + 'px' }, 100);
                    }
                }
                else {
                    this.textarea.css('overflow-y', 'hidden');
                    if (this.textarea.height() < this.dummy.height() + (this.expand_tolerance * this.line_height) || (this.dummy.height() < this.textarea.height())) {
                        if (this.dummy.height() < this.min_height) {
                            this.textarea.animate({ height: (this.min_height + (this.expand_tolerance * this.line_height)) + 'px' }, 100);
                        } else {
                            this.textarea.animate({ height: (this.dummy.height() + (this.expand_tolerance * this.line_height)) + 'px' }, 100);
                        }
                    }
                }
            }

            // Hide the dummy, as otherwise it overflows the body when the content is long
            this.dummy.hide();
        }

    });
})(jQuery);